chickadee » sigma

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Image gallery generator.


sigma [options...] [commands...]


sigma is a simple program for creating a Web gallery of images with a single command. It is based on the igal program by Eric Pop and generates a set of HTML 4.0+CSS-compliant static slides. The appearance of the image gallery can be altered by modifying the default CSS file, as well as the slide template and index page template files that appear in the image directory. Unlike igal, the templates are written as S-expressions, and follow the conventions of SXML.

sigma also checks for the existence of a $HOME/.sigma directory where users can store their own templates, overriding the site-wide /usr/share/sigma.

sigma relies on the ImageMagick package, and if sorting by image date is desired, it can use the exif program to extract EXIF date information from JPEG files.

The convert command from the ImageMagick package is required to process image files and the identify command enables sigma to include size information in the HTML it generates and to determine whether large images need to be rescaled.

If the -c option is used, sigma creates a .captions file, which contains captions to be inserted under each slide. The captions must be in S-expression format and may include SXML tags. Each caption entry can be in one of two forms:

The first element is the image file name, and the second element is the caption. The file name and the caption are required. They can be followed by any number of options keywords. The only option keyword currently recognized is hl, which indicates that the slide should be included on the optional highlights page.

Entries of this form be used to specify captions for subfolders.

To add any comments to this file or to exclude any images from the slide show, add a semicolon the beginning of their respective lines. You may also change the order of images in your slide show at this time.


galleryCreate an image gallery (default if no command given)
thumbsCreate image thumbnails (implicit when gallery is also given)
sortSort images by EXIF date or file creation date
cdimageCreate a CD image containing the image slides
cleanClean generated files


-awrite image sizes under thumbnails on index page
-cfirst generate and then use captions
-Clike -c, but preserve file names as captions
-d DIRoperate on files in directory DIR (default: .)
-fforce thumbnail regeneration and scaled slides
-g TITLEgallery title (default: Default Gallery Title)
-kuse the image captions for the HTML slide titles
-Rrecursively descend subdirectories
-t DIRplace gallery files in directory DIR (will be created if it doesn't exist)
-uwrite captions under thumbnails on index page
-Uwrite slide names under thumbnails on index page
-xomit the image count from the captions
-y Nscale all thumbnails to the same height (default: 75)
--adlike -a, but write only the image dimensions
--aslike -a, but write only the file size (in kbytes)
--author=AUTHORspecify author name (default: $USER)
--con=OPTSoptions to pass to convert
--cd-dir=DIRdirectory for CD image output (default: $HOME/tmp)
--cd-file=DIRname of CD image file if --gcd is not specified (default: Photos)
--gcd=TITLElike -g, but also sets CD image file name
--hlscreates a highlights page
--hls-maincreates a highlights page as the main page
--html-ext=SUFFIXsuffix of output HTML files (default: html)
--index=NAMEname (without suffix) of the main thumbnail index file (default: index)
--hindex=NAMEname (without suffix) of the highlights index file (default: hindex)
--inuse image file names for the HTML slide files
--topcreate index pages for directories that only contain subfolders
--tp=PREFIXsets the thumbnail image prefix (default: .thumb_)
--sp=PREFIXsets the slide image prefix (default: .slide_)
--upcreate Up links even in top-level image galleries
--verbose=LEVELset verbose mode (0: quiet; 1: info; 2: debug)
--wwwmakes all SIGMA files world-readable
--xy=Nscale thumbnails to N pixels in their longer dimension
--yslide=Nscale slides to the given maximum height
--output-htmloutput gallery files in HTML format (default)
--html-ext=SUFFIXsuffix of output HTML files (default: html)
--output-wikioutput gallery files in wiki format
--wiki-ext=SUFFIXsuffix of output wiki files (default: wiki)
-h, --helpprint help


/usr/share/sigma/index-template.scmThe default index template file.
/usr/share/sigma/slide-template.scmThe default slide template file.
/usr/share/sigma/sigma.cssThe default style sheet.

sigma also checks for the existence of a $HOME/.sigma directory where the user can store their own templates, overriding the site-wide /usr/share/sigma.


  ## Creates an image gallery using the image files 
  ## found in the current directory and its subdirectories;
  ## uses directory album to write the HTML files and slides;
  ## writes image sizes and captions under the thumbnails on the index pages;
  ## creates and reads .captions file; resizes the slide images to a maximum
  ## height of 500 pixels

  sigma -a -c -u -R --yslide=500 -t album  

About this egg


Ivan Raikov

Version history

Updated use of find-files [thanks to Christian Kellerman]
Using installation-chicken-home to install template files
Added regex as a dependency
Added functionality for generation of gallery files in wiki format
Prevent empty "next" links from being created (thanks to Christian Kellerman and Snader_LB)
Bug fix in the handling of option cd-dir (thanks to Christian Kellerman); switched to using wiki documentation
Bug fix in default command-line options handling
Command-line handling converted to using getopt-long
Bug fix in command-line handling
Bug fix in filter-subfolders
Ported to Chicken 4



Copyright 2007-2013 Ivan Raikov.

Based on the igal program by Eric Pop.  
ISO 9660 image creation code based on code by Walter C. Pelissero.

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or (at
your option) any later version.

This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
General Public License for more details.

A full copy of the GPL license can be found at